Manufacture of hollow articles



T. M. HAL'sALl. MANUFACTURE l00;? `HOLLOW ARTICLES Filed Feb." 1'?,V1941 wwf M NwAnJ MMM, MW@

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Amongst tiresome iproductionf oifa' Lcor available the lcor may bei'nad'er eith vall the l material comprisingnthew ,core `from the 1coregmaterlal;lnadvetentlygremaining::inside thef. article may impairthe workinrcf thev mecha- 1 Y nismo By terial will4 `be removedirom theinterior-'oi' the hollow :artic1e. I propose to form' `around the core adeformable coyeringwhich will surround the corematerial. The coveringcoat which I prefer to `be elastic, may conveniently bemade of latex andappliedto the-outside of the core,

l ablegen positions. AWheive-L ;the `c ore isto kbe .re--

move through?ayrelativelyLsmall Opening fran-y eshavd-benfem oyedxandthe,

tliejiisel of thenresent" invention, it is posi sible to absolutelyensure that all theco're ma-- byfmoldina spraying, dipflninstances wherefor example,`ittls convenf ien leavealarge openinginthe molded ar-"tiolethe flexible-r covering ,n'eed/not iorlnga closed sack 'aroundthecore.; I xigsuch'instance-lt is vsulfcierit-" to'- completelyjcover jthe particithe "core l hic toro'jects inwiheiniol by en svnended E r hepenefndgli'ojtl' A Y nes. of; thear'ticle to .be molded. e

In the accompanying` drawing f i for [purposes 'of illustration only,"`certain presently 11 preferredembodiments` of my: invention.

Figure 111s aview in `section of a hollow core ioljmemandwith thecorestill'inside;

Figure- 4 is a View', partly in section,. showing y the completed 1artic1e, with the s core `broken and beingfremovedinside and with theflexible cover- Ang; Y Figure 5 is a-viewjpartly in section showing ahollow article of Ya diierent shape with the frangible core `andiiexible coveringstill'inside, and Fgurerepresents amodication pf theint ventionsomewhatsimilartolthat shown in `Figure5.

Inthe drawing wherein likereference numerals 45 a re app 1ied,to similarpartsfin the several views, numeral i0 indicates afcore ormoldwhich is.r ;epresented asgbeing hollow.5` This core is made i?1 o`n1 l a-Iangiblematerial such as plaster of Paris, glass, clay, etc., and byany desired operation. It is made thick enough to enable the core towithstand the strains imposed on it by the operations incident toformingf'the desired article around the core. 'I'he outline of the corei corresponds to the desired contour of the inside 55 of the article tobe formed therearound. It is any suitable substance, such as rubber,plaster,y papier-mch', or organic-2 plaster appliedm Yany beyond thecon` 1 have shown Y fof the'dimensionsdesired. to formthe interior ofpleted` article in the outside mold in which it is also withincontemplation to make the core substantially solid, so long as it may bereadily broken up as desired at the end of the article formingoperation.

The' frangible or shatterable core or supporting Vmember I has appliedthereto a flexible coating or layer II. 'I'he coating or skin may beformed from anelastic material such as rubber. applied in any way, forexample 'by dipping in a suitable latex mixture or by spraying such amixture on the outside'of the core. I prefer to use a thin coating, buta relatively thick coating may in many cases be advantageously employed.In most instances it is desirable that the latex be applied so as not toadhere to the core material, although in other instances such a practiceis not necessary. VMethods of applying latex are well known .and incommon use.

lThe material for forming the completed ar ticle I2 is applied directlyover the outer surface of the flexible coveringV II. The material maybe, rubber, plaster of Paris, papier-mch, organic plastic, or evenmetal,and may be applied in any known way such as by. dipping, spraying, plas--tering, molding, etc. In Figure 3 a molding operation isdiagrammaticaily shown. There the flexiblyl covered core I0-I| is placedinside a suitably contoured mold I3, the inner surface I4 of which is'contoured to the outside shape of the completed article desired. Thecore is placed in the mold cavity so that the outer surface of theflexible covering I2 isthe desired distance Y from the inner surface I4Vof the mold. 'Ihe intervening space is then filled through the openiing I5 with the desired material'to form the Vmaterial forming the coreI0 is broken up, in- .side the flexible closed'sack II and the sack--and vthe broken core inside of it are removed.Y

through an opening I6 in a convenient location in thel wall of theformedvarticle'Iz. The open- Y -V ing may be smaller .than thedimensions of the formed article.

Figure 4. Y

YWhere a large opening is available in the finished article, thearrangement shown in Figure 5 may be employed. 'The core Illa extendsbeyond the `article I2a, and the flexible coating IIa is applied as byspraying or dipping over the core so as to form4 in effect, anopenendsack.

In the modification shown in Figure 6, the sackI Ib, surroundingthefrangible core IUb, is formed from sheet material, such as sheetrubber or4 an open end sack which is stretched over the core IIIb andtheends tied at I1 to form a closed sack.

When the article is formed as shown in either Figure 5 or Figure 6, thefrangible core is removed while inside the flexible sack.

` Either of these modifications is useful where the finished articleis'formediby methods other than by the employment of an outer mold asshown in Figure 3. Spraying, dipping, and plastering, 'for example'maybe advantageously used.

The operation is illustrated in While lI have described certainpreferred em bodiments of my invention it is to be understood thatvarious changes may be resorted to within A the scope oi' the followingclaims.

I claim as my invention:

1. A core for use in forming hollow articles, comprising an innerportion of frangible ma-v terial and an overlyingcoating of flexiblematerial in ncontact with the inner portion.

2. A core for use in molding, comprising a shatterable supporting memberand an overlying flexible coating.

3. A corefor use in molding, comprising a hollow supporting memberformed of frangible material andan overlying flexible layer.

4. A core for use in molding, comprising a hol` low supporting memberformed of frangible ma- .terial and an overlying flexible layer entirelysurrounding the member.

5. A core for use in molding, comprising a hollowsupporting memberformed of frangible material enclosed in a rubber sack.

6. A core for use in forming hollow articles,

comprising an inner portion of frangible ma' terial which extends beyondthe article to be formed, and a coating of flexible material overlyingthe inner portion. l

'7. The method of forming a hollow article having an oening thereincommunicating with the interior thereof, which comprises forming a coreof shatterablematerial, covering the vmaterial with an overlyingfiexible coating, forming the article on the coating, shattering thecore and thereafter removing the core fragments from the article withand inside the coating.

8. The method of forming a hollow article having an opening thereincommunicating with the interior thereof, which comprises forming a coreof a shatterable material, covering the material with an overlyingflexible coating, forming the article on the coating, thereafterremoving the core along with theskin through said opening.

9. The method of molding a yhollow article having an .opening leading tothe interior thereof, which comprises shaping the moldable materialabout a shatterable core encased with a form fitting flexible skin,thereafter shattering the core and removing Athe core fragments enclosedwithin the skin through said opening.

10. The method of molding a vhollow article having an opening. leadingto the interior thereof, which comprises shaping the moldable materialabout a shatterable core encased within .Y a' form fitting flexibleskin, thereafter shattering the core and removing the core fragmentsalong

